Chelsea thought it was "just a cold" at first. She picked her mother some flowers from their garden.

As time passed, Chelsea began to grasp the struggles her mother was enduring. She said it finally hit her when Betty told her she could barely make it up the stairs sometimes.

"She said there were times when she felt like dying," Chelsea said.

Today Betty Shock is healthy, having beaten cancer several months after that emotional Friday afternoon. Chelsea is set to graduate this month from John Carroll, finishing a high school career that was highlighted by three years of varsity lacrosse and countless hours spent working with Shock Cancer — an organization she founded to raise money for cancer awareness. Chelsea's dedication to fighting cancer led to her decision to forgo her senior season of lacrosse — a sport she played for 13 years.

For her selfless choice, The Baltimore Sun has selected Chelsea as the 2011 recipient of the Hayley Milbourn Integrity Award, honoring a local high school athlete who demonstrates extraordinary character.

The seeds of Chelsea's decision to give up lacrosse were planted years ago, back when Betty — a vice president at GameStop — was still battling her disease.

"It was all hard for her to deal with at 11," Betty said. "I went through the process strong, showed no emotions. I wanted it to be business as usual at home. It was an absolute mistake. We all need to show grief and emotion."

Soon after her mother — who has undergone 12 chemotherapy sessions and 20 radiation treatments — was diagnosed, Chelsea began getting called out of class to talk to fellow students whose parents recently had been stricken with cancer. It was fitting. Chelsea was helping people.

It felt right.

"I understood then that was what God wants me to do with my life," Chelsea said.

Thus began Shock Cancer. It started with raising money at restaurants and local events. Now the Shocks are running marathons.

Betty began with the Baltimore Marathon in 2005. Chelsea wanted to run with her mother but didn't train, prompting Betty to deny her permission to participate. Chelsea was relegated to enthusiastic cheerleader.

"I saw her face when she crossed the finish and never wanted her to run alone again," Chelsea said.

Mother and daughter now work out with Team in Training, an organization formed to help raise money for cancer through running marathons. According to its website, the foundation has raised $1 billion to fund cancer research.

The more involved Chelsea became with Shock Cancer and Team in Training, the less time she had for lacrosse. Giving up the sport she loved wasn't an easy decision. She made the varsity squad her freshman year, an impressive feat at a local powerhouse like John Carroll. Patriots coach Krystin Porcella was one of the first people Chelsea consulted about the decision.

"I went and talked to [Porcella] on the verge of tears," Chelsea said. "She said she understood if I didn't play. She said I would always be a part of the team."

Porcella called Chelsea "vocal, generous and unselfish" and said she was missed this season. The Patriots went 9-4, falling in the quarterfinals of the Interscholastic Athletic Association of Maryland A Conference tournament.

"She was very much a leader for us," Porcella said. "I do think she made the best decision for her. But I was disappointed she wasn't going to be on the team and it definitely affected us not having that positive around."

With no lacrosse, Chelsea and Betty spent much of their free time training. The pair traveled to Disney World in January and completed The Goofy Challenge, a grueling trek consisting of a half-marathon one day and a full marathon the next. The round trip comes out to 39.3 miles in 48 hours. After running the half-marathon, the Shocks had to wake up at 2 o'clock the next morning to start the 26-mile behemoth.

"The half-marathon was a piece of cake," Chelsea said. "The full marathon was almost impossible. By mile 13, my feet were throbbing. My mom started singing Miley Cyrus to keep me going."

Chelsea plans to attend Loyola in the fall, majoring in either psychology or biology, with an eye on eventually attending physician assistant's school. She hopes to work in pediatric oncology — helping kids afflicted with cancer — someday. Betty couldn't be prouder of her daughter's passion for fighting the disease.